I think it’s easy to use the ‘headroom’ concept (which is at its best the ability to play what you hear musically without any technical constraints) to fall into some practice ideas that can be a little useless, or maybe very unpractical is a better term. It might give you ‘headroom’ to practice paradiddles in quintuplets over sextuplet double paradiddles in the feet, but you could also use that time practicing functional, musical stuff that you’ll use on actual gigs to a high level...also giving you headroom, but functional headroom. Things you’ll use should always be the goal.
Practice things that are functional and that you will use. Just go further with those things than you will use on gigs. For example, instead of practicing something like the above paradiddles example, get some hip Garibaldi linear funk coordination going and really build on those concepts to a high level. Or practice getting foot or left hand rhythmic freedom with a bunch of different Afro Cuban bell patterns. Or whatever suits your musical needs.
Don’t feel you need to practice stuff just to practice stuff. Play things that will be applicable musically, but just play them really well and try to have as much freedom as possible in that area, then move on to the next.